Found this link on here today at work and did some reading: http://www.gulland.ca/fhs/hhstoc.htm Excellent. He suggests insulating the chimney chase. My 6" class A is going to be in a chase on the outside of my house. The height from stove to top will be approx 32 ft. I was thinking my draft would be so strong it would be good to install a damper on the stove pipe. My stove will be a Woodstock Progress. If there is a reason to insulate the chase around the class A I need to plan for it. What do you think?